In the manufacture of multilayer ceramic (MLC) substrates for integrated circuit packages, it is necessary to punch via holes through the ceramic green-sheets. Typical ceramic sheets can require thousands of closely-spaced holes, for example on the order of 0.05 inches (0.127 cm) in diameter.
To maintain adequate through-put in the manufacture of these packages, it is usually necessary to punch many of these holes at the same time: i.e. in parallel. This requires the use of many closely positioned and simultaneously controlled punch mechanisms. High power requirements, substantial heat dissipation, and physical size limitations are exemplary of many of the problems encountered in trying to provide adequate punching systems.
Coneski, A. F., et al., "Punch Programmer with Magnetic Retract", IBM Technical Disclosure Bulletin, Vol. 26, No. 7A, pgs. 3173-3175 (December 1983) shows a punch mechanism utilizing a permanent magnet to retain a plunger in a de-energized position. A solenoid-type actuator is utilized to energize the mechanism, overcome the magnetic field of the permanent magnet, and effect the punching action.
Cochran, T. J., and Haas, R. G., "Automated Punch Apparatus for Forming Via Holes in a Ceramic Green Sheet", IBM Technical Disclosure Bulletin, Vol. 20, No. 4, pgs. 1379-1380 (September 1977) shows a punch mechanism utilizing a dual coil solenoid for punching/retracting. Multiple punch mechanisms are arranged in close proximity and under computer control to provide desired hole patterns.
U.S. Pat. No. 1,138,804 to P. J. Simmen shows a punch wherein a spring is used to maintain a plunger in an unenergized position. A solenoid is provided which, when energized, overcomes the force of the spring to move the plunger to a neutral position. This movement of the plunger effects the perforation of a piece of paper.
U.S. Pat. No. 3,709,083 to Doherty shows an electric punch press utilizing a spring to maintain a plunger in an unenergized position. A foil-wound solenoid is provided for overcoming the force of the spring to drive the plunger and activate a punch. When the solenoid is de-energized, the spring returns the plunger to the starting position.
Solenoid-driven punch mechanisms, several types of which are illustrated above, exhibit the disadvantage of providing relatively low punching power for their substantial size and electrical power requirements. To punch MLC green-sheets of the type discussed above, it would be very desirable to provide a mechanism which provides increased punching power while requiring minimal space and electrical power.